Peoria woman back in jail for allegedly beating cousin to death with hammer last year

Brianna Zerth, 30, is accused of beating 33-year-old Peter McKenna Jr. to death with a hammer at a Peoria home in May 2022.
Published: Jul. 24, 2023 at 2:38 PM MST|Updated: Jul. 24, 2023 at 5:11 PM MST
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PEORIA, Ariz. (3TV/CBS 5) — A Peoria woman has been arrested again in connection with the murder of her cousin over a year ago. Peoria police say 30-year-old Brianna Zerth was arrested on a Maricopa County Grand Jury warrant late last week for the murder of 33-year-old Peter McKenna Jr.

Zerth was arrested for the first time on Wednesday, May 5, 2022. Just after 12 p.m. that day, police responded to a medical call at a home near 111th and Olive avenues and found McKenna dead inside. Court documents at the time said an officer noticed several injuries to McKenna’s back, which were determined to be puncture wounds from a claw hammer. Blood was found covering several walls in the home, and a hammer was found near McKenna’s body.

Per the same documents, Zerth told investigators that her cousin, McKenna, had been staying at the home for about three weeks after Zerth’s mother died and that they had been drinking alcohol the night before. Zerth reportedly said she and her cousin eventually began fighting throughout the house, but details about what happened were “blurry.” She said she woke up the next morning to find McKenna face down on the floor, covered in blood. Zerth said she then covered McKenna with a jacket, cleaned the area, picked up pieces of glass so her 6-year-old daughter wouldn’t step on it, and then called the police.

Zerth was booked later that day for charges including second-degree murder, tampering with evidence and aggravated assault but was released from jail a short time later when the Maricopa County Attorney’s Office sent the case back to Peoria police seeking “additional information.”

In June of 2022, Zerth was arrested again for aggravated assault after allegedly trying to run her boyfriend over with a car while under the influence. A judge later granted supervised release. Last October, Zerth was arrested for a third time on criminal damage and disorderly conduct charges. Those cases are pending.

Just before 4 p.m. last Friday, detectives arrested Zerth at her new home, two doors down from the house where McKenna was killed. She was booked into jail for second-degree murder, aggravated assault with a deadly weapon and tampering with evidence.

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